Mammosite Partial Breast Irradiation

Partial Breast Irradiation (PBI) is one of the treatments offered at Piedmont Hospital (our practice) for patients with small breast cancers. It is a technique in which just the tumor cavity, representing the area where the tumor was removed from and approximately 1 cm of normal breast tissue around it, is treated with radiation. In appropriate candidates the risk of a local recurrence (cancer returning where it was originally present in the breast) is comparable to treatment with full breast radiation. The difference lies in the fact that PBI treats only the lumpectomy cavity rather than all the breast tissue. Usually the patient will visit with both her surgeon and radiation oncologist prior to surgery to discuss her candidacy for PBI. Recent consensus guidelines from the American Society of Therapeutic Radiation Oncology help the radiation oncologists to guide patients in deciding whether PBI or treating the full breast is most appropriate. Generally, this treatment is favored for small breast cancers in postmenopausal women whose tumors would be expected to respond to hormonal treatment. The final pathology after surgery can confirm or dissuade that decision.

There are many ways to accomplish partial breast irradiation. The most common way is using a balloon device placed in the breast, usually a few days after the surgery once the pathology results are available to ensure a woman is a good candidate for the procedure. Currently two balloon devices are on the market. The first product approved by the FDA in the early 2000s is the Mammosite™, in which a 1cm symmetrical margin is treated around the resection cavity. A woman must have at least 7mm of breast tissue above the balloon towards the skin in order to have Mammosite treatment. Another balloon technique that recently came on to the market is called the Contura™ balloon technique. This balloon has more than one catheter to receive the radioactive source so it is able to safely treat cavities that are closer to the skin. Alternatively, PBI can be accomplished using a linear accelerator, the same machine that treats patients that have daily treatments, like the women who are receiving full breast irradiation

Once a balloon catheter is placed in a woman's breast, the patient sees the radiation oncologist. A simulation (planning session) is performed. This generally takes 30-45 minutes. Typically, the patient then begins the 5-day course of treatment a few days later. Treatments are given twice daily with a break of 4-6 hours between treatments. There are a total of 10 treatments. Prior to each treatment, there is verification to ensure the balloon is in the proper place (tumor cavity) in the breast and has not changed from the planning position. Then the catheter portion from the balloon that is outside of the patient's breast is connected to a machine which has a wire containing radiation. The radiation source is called Iridium 192. The wire with radiation goes down the catheter and stays there for a few minutes, delivering the prescribed dose of radiation. Once completed, it goes back into the machine. The catheter is disconnected. The patient no longer has any radiation and may leave the radiation suite. She returns at the next time for her next treatment. At the end of the 10 treatments, the saline (water) in the balloon is removed and the catheter is removed from the woman's breast.

Side effects are usually delayed until after the radiation is completed. They include redness of the skin overlying where the balloon was on the skin. This varies depending on how close the balloon is to the skin. Patients may also experience some mild tenderness of the chest muscle below the balloon. Patients in our practice are kept on antibiotics while the balloon device is present to decrease the risk of an infection.

Peachtree Radiation Oncology services has been performing partial breast irradiation procedures using the Mammosite device, and more recently, the Contoura device since FDA approval of these devices.

If you have a diagnosis of breast cancer, Drs. Fred Schwaibold and Adam Nowlan can discuss this treatment with you.

Our physicians are highly experienced in treating all malignant and benign conditions for which radiation therapy is indicated. If you should have a question about whether or not a particular treatment is offered in our office, please feel free to contact our office by telephone.